Tubes, such as those used to hold toothpaste, caulking material, silicon sealant and the like, for either domestic or industrial use, are preferred containers when a relatively small amount of viscous material needs to be stored conveniently for instant use. Originally, such containers were made from ductile metal and the materials therein were forced out by rolling the tubes up from their filling end to their nozzle end. With the advent of suitable flexible plastic materials, metal tubes have almost entirely disappeared from the marketplace. This has occurred because plastic tubes have less tendency to rip and tear, are generally more economical to manufacture and are relatively inert to various materials stored therein which heretofore would attack metal containers.
The convenience and economy of such tubes is lost if they are emptied in a careless manner so that much of the contained material becomes trapped in wrinkles in the tube. Therefore, a variety of devices have been designed which attempt to assure easy complete emptying of such tubes. Some devices, such as are shown in U.S. Pat. No. 4,448,333 to FERRARI and U.S. Pat. No. 4,579,254 to PUSKARCIK, are rachet-type devices which squeeze the tube and gradually move thereup. Such devices are not always desirable as they tend to leave residual pressure in the tube which can cause unwanted flow, either before the tube cap can be reapplied or upon next opening. Others, such as shown in U.S. Pat. No. 2,390,314 to MASSEY and U.S. Pat. No. 2,790,579 to WOLDORF nibble up the tube and are more adapted for the old style metal tubes than modern resilient plastic tubes. Some are slider devices adapted to be merely pushed up the tube, such as shown in U.S. Pat. No. 2,554,975 to BENDICK and U.S. Pat. No. 4,159,787 to WRIGHT. WRIGHT discloses a more sophisticated device having a forwardly facing extension to push material out of the tube when the tube is nearly empty and streamlined internal surfaces so that the tube slides easily through the device. WRIGHT and others, such as ADAMS, U.S. Pat. No. 3,248,012 also include a releasable clip for those instances where it is difficult to get a sleeve device over the end of the tube in the first place. However, with all these devices there is still room for improvement.